BAITED YELLOW RECTANGLES FOR TRAPPING APPLE MAGGOT FLIES 



Ronald J. Prokopy 

 Department of Entomology 



There are about a dozen major insect-type pests o£ apples in 

 Massachusetts. Some of these, svch as mites, rosy and green aphids, 

 leafhoppers, and scale insects attack the vegetative parts of the 

 tree and can be tolerated in small or moderate numbers without eco- 

 nomic injury. In unsprayed orchards, predators and parasites aid 

 in suppressing these vegetative pests at population levels which are 

 not injurious. Most of our common orchard sprays are highly toxic 

 to predators and parasites, and hence we must spray additional ma- 

 terials to prevent these vegetative pests from reaching economically 

 injurious levels. 



There are other major pests of apples, such as plum curculio, 

 codling moth, red-banded leafroller, sawfly, and apple maggot whose 

 larvae (worms) feed directly on or in developing or mature fruit. 

 Even small numbers of adults of any one of these fruit pests in a 

 commercial orchard can cause economic injury. Numerous studies 

 and observations have shown that the apple maggot is one of the 

 most damaging of these pests in the northeastern states, including 

 Massachusetts. In unsprayed trees, usually 95-100% of the fruit 

 is infested by apple maggot larvae. 



In commercial orchards, the last 3-5 insecticide cover sprays 

 of the season are directed principally against the apple maggot. 

 In nearly all cases, I expect that most or all of these maggot 

 cover sprays are applied as a preventative, irrespective of whether 

 or not flies are actually present in the orchard and constitute an 

 economic threat. Development and use of effective traps to monitor 

 maggot fly populations would tell a grower when, if at all, maggot 

 flies first appear in his orchard, and when they have died out for 

 the season. With this knowledge, the first maggot spray could be 

 delayed until first fly capture on the traps, and the last one or 

 two maggot sprays eliminated if no further maggot flies were cap- 

 tured. In this day of rapidly increasing pesticide costs and re- 

 strictions on pesticide usage, any pesticide reduction without sac- 

 rifice of fruit yield or quality will make for greater profit and 

 less environmental damage. 



I've been studying apple maggot fly behavior for several years, 

 and in this article will relate how certain of these studies have 

 aided in the development of effective apple maggot traps. 



Apple maggot flies emerge from overwintering puparia (cocoons) 

 in the soil. They spend the first week or two of their lives feed- 

 ing on insect honeydew (the sugary secretion of aphids and similar 



